object SetDemo {
  def main(args:Array[String]):Unit = {
    var members = Set("张三","李四","王五")

    members += "李四"
    members += "赵六"

    println("志愿者社团成员：")
    for (member <- members){
      println("-" + member)
    }

    val hasZhangsan = members.contains("张三")
    println(s"是否有张三？$hasZhangsan")

    println(s"实际成员数：${members.size}")
  }
}
